Java生成图片

参考博客：

1.利用Data URL(data:image/jpg;base64,)将小图片生成数据流形式
https://www.lvtao.net/dev/php-image-data-url.html
2.Java生成图片
http://blog.youkuaiyun.com/liuxin191863128/article/details/38081465

package image;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.font.FontRenderContext;
import java.awt.geom.Rectangle2D;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;

import sun.misc.BASE64Encoder;

/**
 * 图片的相关操作
 * @author 张爽
 * @date 2017-8-2
 */
public class ImageOperation {
	public static void main(String[] args) throws IOException {
		CreateImage.createImage();
	}
	
}
/**
 * 生成图片
 * 1.将图片写到磁盘里
 * 2.将图片写到流里
 * 3.拿到图片的base64
 * 参考博客：
 * 	1.利用Data URL(data:image/jpg;base64,)将小图片生成数据流形式
 * 		https://www.lvtao.net/dev/php-image-data-url.html
 *	2.Java生成图片
 *		http://blog.youkuaiyun.com/liuxin191863128/article/details/38081465
 * @author 张爽
 * @date 2017-8-2
 */
class CreateImage {
	/**
	 * 创建一张图片
	 * 图片存放路径：E:/学习笔记/createImage.jpg
	 * 1.将图片写到磁盘里
	 * 2.将图片写到流里
	 * 3.拿到图片的base64
	 * @author 张爽
	 * @throws IOException 
	 * @date 2017-8-2
	 */
	public static void createImage() throws IOException {
		int width = 100;
		int height = 100;
		String content = "你好";
		File file = new File("E:/学习笔记/createImage.jpg");
		Font font = new Font("Serif", Font.BOLD, 10);
		
		BufferedImage bufferedImage = new BufferedImage(
				width, 
				height, 
				BufferedImage.TYPE_INT_RGB
			);
		
		Graphics2D graphics2D = (Graphics2D) bufferedImage.getGraphics();
		graphics2D.setBackground(Color.WHITE);
		graphics2D.clearRect(0, 0, width, height);
		graphics2D.setPaint(Color.RED);
		FontRenderContext fontRenderContext = graphics2D.getFontRenderContext();
		Rectangle2D stringBounds = font.getStringBounds(content, fontRenderContext);
		double x = (width - stringBounds.getWidth()) / 2;
		double y = (height - stringBounds.getHeight()) / 2;
		double ascent = -stringBounds.getY();
		double baseY = y + ascent;
		graphics2D.drawString(content, (int)x, (int)baseY);
		
		// 1.将图片写到实体图片里 
		ImageIO.write(bufferedImage, "jpg", file);
		// 2.将图片写到流里
		ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
		ImageIO.write(bufferedImage, "jpg", byteArrayOutputStream);
		// 3.将图片以base64的形式展示
		BASE64Encoder base64Encoder = new BASE64Encoder();
		byte[] byteArray = byteArrayOutputStream.toByteArray();
		System.out.println("data:image/png;base64," + 
				base64Encoder.encodeBuffer(byteArray).trim());;
	}
}